Methods and apparatus for signalling and communicating



Dec. 15, 1959 R. 'r. MacFARLANE ETAL 2,917,581

METHODS AND APPARATUS FOR SIGNALLING AND cowumcmuc Filed April 26, 1957 s Sheets-Sheet 1 fx rm'nmon ED 39 VOLUME INVENTORS P. 7." MACFAPLAA/E 6. C. PASS/WAN O. A BPAMS BY ag; Marngy 1959 R. "r; M FARLANE EIAL 2,917,581

METHODS AND APPARATUS FOR SIGNALLING AND COMMUNICATING Filed April 26, 1957 3 Sheets-Sheet 2 AV'T il Q u Q m N v IINVENTORS P. I MAcFAPLA NE 8. C. PASSMAA/ D. ABBA/v75 Gil-ohm) United States Patent METHODS AND APPARATUS FOR SIGNA LLING AND COMMUNICATING Roderick T. MacFarlane, Westfield, Daniel Abrams, Parsippany, and Barry C. Passman, Livingston, NIL, assignors to Simplex Equipment Corporation, Bloomfield, N.J., a corporation of Delaware Application April 26, 1957, Serial No. 655,227 9 Claims. C1. 179-1) The present invention relates to methods and apparatus for signalling and communicating, and more particularly to a combined annunciator, intercommunication and public address system. The invention has particular application to an electrical ordering system and especially to a system wherein a number of sub-stations are supplied with a common program and the sub-stations can each individually be connected in intercommunication fashion with a central station for individual two-way communication between a single or a group of sub-stations and the central station. The particular system illustrated in the drawings and described in detail in the specification was developed especially for use in drive-in restaurants. However, it will be appreciated that the present invention has other applications and is not limited to the drivein restaurant field.

In the operation of a drive-in restaurant which does not have an electrical ordering system, the waitress is usually required to make three trips from the kitchen or other central stations to patrons parked in automobiles in their respective bays. The first trip is made in order to take the order; the second trip is made in order to bring the order and to collect payment; and the third trip is to pick up empty serving trays. All this is time consuming and wasteful of man power, particularly during heavy rush periods. It also is at times annoying to patrons who may have waited a considerable length of time before the attention of a waitress can be obtained either to take an order or to remove the tray used by a previous patron, the delay in removal resulting in further delay and annoyance to new patrons and loss of business to the restaurant owner. If the patron desires entertainment, he has to use his own car radio, thereby wearing down his own battery by operating the radio with the engine shut otf.

It is an object of the present invention to provide improved methods and apparatus for signalling and communicating.

It is another object of the invention to provide an improved system which will normally furnish entertainment to a patron while parked at a drive-in restaurant bay and which will effect quick change-over and communication between the patron and a central station when desired to eliminate extra trips by the waitress and delay for the patron.

It is another object of the invention to provide an intercommunication system wherein messages can be transmitted from a central station to a series of patrons at different stations who are waiting to put in orders, wherein the central station is able to advise such'patrons simultaneously at such series of stations as to special features and the like without disturbing entertainment furnished other patrons who have already ordered.

It is another object of the invention toprovide a unique communication system wherein'selection of a specific substation out of a series of a substantial numberof substations can be made from a central'station by means of switches arranged so that a total of a relatively small number of selector switches permits selection of any sub station, rather than having to provide a different individual switch for each different sub-station. For exam ple, selection of any one or" one hundred dilierent substations may be etfected by providing a total of only twenty selector switches inter-connected according to a matrix selection system.

It is a further object of the invention to provide an electrical ordering system for drive-in restaurants which can be installed for a certain minimum number of substations and which can be subsequently expanded for additional sub-stations without disturbing existing connections at the central station and without incurring duplication of cost other than those necessary for the additional sub-station connections.

It is a further object of the invention to provide an inter-communication and public address system having a central control station provided with apparatus which is of relatively small size and weight and which is readily operated by inexperienced and untrained personnel, and wherein the bulky major components may, if desired, be remotely located from the central control station so as to be out of the way and in any convenient location.

In accordance with one aspect of the present invention there is provided a system comprising a plurality of sub-stations each having a combined loudspeaker-microphone, which may also be referred to as a transducer. Under ordinary or quiescent conditions, all sub-station transducers are connected to the output of a program source, such as a phonograph, tape recorder or radio, to provide entertainment for patrons or prospective patrons located at respective of the sub-stations. A central station is provided with a loud speaker-microphone transducer, and a switching connection arranged to connect this transducer selectively in a receiving or transmitting condition. The central station is further provided with a composite sub-station switching circuit which is capable of operative connection in three conditions. In the first condition, this circuit functions to connect the sub-station transducers to the program source; in the second condition it connects a single selected sub-station transducer to the central station transducer; and in the third condition it connects the central station transducer simultaneously with all of those sub-station transducers where patrons have indicated'their desire to order and are-still waiting to place an order.

As an important feature'of the invention, we provide a plurality of control means operatively connected with the program source which may be a music source, and with the central'station transducer, respectively, to control a condition of the composite sub-station switching circuit. One of these control means includes novel switching arrangements preferably operated with relays and arranged in a rectangular matrix having number and letter selector switches, the switches being so interconnected that only a relatively small total number .of switches, for example twenty switches comprising ten letter switches and ten number switches, are sulficient to permit operation of any one of sub-stations.

It is yet another feature of the invention to make unique provision for standby or common talk wherein the. sub-stations which have not signalled and those which had signalled and placed their orders are left'undisturbed, whereas one of the control means connects the central station transducer simultaneously with those other sub-stations which have signalled the centralstation and are still awaiting an answer, and whereas connection is simultaneously also made with another sub-station whose corresponding number and letter buttons may have just been depressed at the central station and have not yet been released by the operator at the central station.

An important aspect of the invention relates to the specific application of the system to an electronic ordering system for drive-in restaurants wherein the program source provides entertainment such as, music from a radio, phonographvor tape recording machine. The central station is provided with an amplifier and a microphone-speaker type transducer. The central station has a control switch so that the amplifier can be used to amplify incoming signals for loud speaker use of the central station transducer or to amplify signals from the central station transducer when it is used as a microphone. At each of the sub-stations there is provided an individual signaling switch. The sub-stations are grouped according to a decimal system, for convenience in a letter-number arrangement of ten numbers '1 through and ten letters A through K (omitting I). The central station is provided with a unique group of pushbutton switches corresponding to the letters (or tens in a decimal system) and to the numbers (or units in a decimal system). With suitable circuitry it is then possible by merely depressing one button in the letter group and one button in the number group to be able to select any one of one hundred sub-stations.

It is a further feature of the invention that the central station is provided with a common talk control switch, also referred to as a standby switch, which causes the central station speaker to be connected as a microphone through its central station amplifier with all those substations which have signalled the central station that they are ready to place their orders, without, however, disturbing any other sub-station, and without requiring depression of individual push buttons for individual substations. This common talk control switch so functions with the aid of relays that the output of the central station voice amplifier appears at a separate line, the impedance of which can be matched as desired. The output of the same voice amplifier, when it is to be connected to a particular sub-station by depressing the proper letter and number push buttons, will appear at a different line, which may be matched for a different impedance. Although in the embodiment illustrated the information in either case originates and is transmitted from the same speaker-microphone at the central station and the same amplifier etc. is used, the communication paths or channels for the common talk and the singlestation talk need not overlap and have been given different nomenclature. Hence, for purpose of clarity, the common talk connection together with the central station microphone and amplifier etc. may be referred to in this general description and claims as a common talk channel while the single-station connection together with the central station microphone and amplifier etc. may be referred to as a single-station channel.

According to still another feature of the invention, when each new patron at a sub-station operates the signalling control switch, also referred to as an order" control switch, this causes energization of an order relay which effects signalling to the central station and which simultaneously transfers the connection of the sub-stations speaker from the program (or music) line to another connection with the common talk line, i.e., to the common talk channel. At this moment, and without further switching required by anyone, the music at the particular sub-station is interrupted, thus indicating to the patron that something has happened. However, no signal from his speaker-microphone can reach another transducer in receiving condition through an amplifier. There is now a choice for the central station operator who has been notified of the operation of the particular sub-station signalling control switch by means of the illunit ation of a respective pair of lights in a group of order indicator lights arranged on a panel in a. novel matrix relation and corresponding to the total number of substations. As one choice, he can operate the common order control switch which will leave the order relay of the particular sub-station undisturbed in its energized condition and which will permit him to reach the particular sub-station and also simultaneously to reach all of those other sub-stations, if any, where the patrons are still waiting to give their orders after having likewise operated their respective signalling control switches and whose order relays are therefore also energized and whose order lights are still lighted. As an alternative choice or a next step, if the central station operator is ready to take the order of a patron who has signalled from a particular sub-station and the operator therefore desires to obtain two-way communication with such sub-station, the operator first depresses the required letter button and number button which operate the particular letter and number switches, respectively, thereby energizing an answer" relay specific to the particular substation. Energization of the answer relay causes interruption of a holding circuit for the order relay specific to the particular sub-station. This serves to restore the order relay to its normal de-energized condition and accordingly it turns 01f from the central station panel the two order lights corresponding to the particular sub-station. Restoring the order relay to its normal inoperative position disconnects the sub-station speaker from the common talk line. However, due to the energization of the answer relay, the sub-station speaker is not transferred back to the program source (music), but instead is connected automatically to the single stationline which connects to the inputof the central station voice amplifier, the output of which is connected to the central station speaker-microphone, so that as soon as the central station operator requests the patrons order, the patron at the sub-station may talk to the central station without any further operation at either the central station or the sub-station. In order to request the patrons order, the central station operator can communicate with the patron at the particular sub-station by operating a talk switch which reverses the input-output connection of the central station amplifier to provide amplification of the voice of the central station operator. When the order has been taken, the central station operator actuates a release mechanism which restores the specific letter and number buttons and switches to normal so that the answer" relay drops out, restoring the individual station speaker circuit to the program (music) source line.

According to another feature of the invention, the answer relay is provided with an overriding connection, so that continued operation of the order" relay by a patron who erroneously believes that he must hold closed his signalling control switch, will not interrupt order and talk connections set-up by the answer relay as determined by the operator at the central station.

According to another feature of the invention in order to communicate with a particular sub-station, the central station operators selection of the particular sub-station is accomplished by means including a group of pushbutton letter switches and a corresponding group of letter relays, each letter relay having at least ten contacts (or a group of pairs of relays in parallel and each pair having, in the aggregate, at least ten contacts),

each letter relay (or pair of relays) being connected so that it can be operated by closing its corresponding letter switch. The letter switches and letter relays represent the tens in the decimal system, each letter switch or its corresponding letter relay representing an additional ten sub-stations. A group of ten pushbutton number switches representing the units in the decimal system is provided. The total number of switches of all letter relays is at least equal to the total number of sub-stations, There is also provided a group of answer relays equal in number t8 the total number of substations, there being a different answer" relay for-each switch of each letter relay. Each of the ten switches of :the A letter relay is connected with its respective answer relay in a different normally open parallel circuit. Similarly, each of the ten switches of the B letter relay is connected with its respective answer relay in a different normally open parallel circuit. Each of the ten switches of each of the other letter relays is similarly connected with its respective answer relay in a diiferent normally open parallel circuit.

The No. 1 number switch is connected in common series circuit relationship with the first switches of all of the letter relays and with the respective answer relays for such first switches. Similarly, the No. 2 number switch is connected in common series circuit relationship .with the second switches of all the letter relays and with the respective answer relays for such second switches. Similarly, for each of the other eight number switches Nos. 3 through 10, the No. n number switch is connected in common series circuit relationship with the nth switches of all of the letter relays and with the respective answer relays for such nth switches. With such unique matrix arrangement, the central station operator may energize the answer relay for a particular sub-station, for example sub-station A-l, so as to obtain intercommunication with such substation in the following manner. The A letter pushbutton is depressed so as to close the A letter switch, thereby completing a circuit through the A letter relay which serves to energize the latter relay and to close all ten of the pairs of contacts (i.e. its ten switches) of the latter relay. However, at this time there is still not established a complete circuit through any one of such pairs of contacts and a respective answer relay of the bank of ten answer relays associated with the A letter relay. By next depressing the required number pushbutton (i.e. the No. 1 button), the No. 1 number switch is closed which thereby completes just one circuit from one terminal of the power supply via the closed A letter" switch and the closed first pair of contacts (i.e. the first switch) of the A letter relay and through such No. 1 answer relay of such bank of ten answer relays and finally via the closed No. 1 number switch back to the other terminal of the power supply.

Other objects, advantages, and features of the invention will appear from the following description of a specific embodiment of the invention given by way of example as relating to electronic ordering systems for drive-in restaurants.

In the accompanying drawings,

Fig. l is an oblique view of one form of compact central station control cabinet in accordance with the present invention;

Figs. 2a and 2b are schematic circuit diagrams of different portions of one embodiment of the present invention in the form of an electronic ordering system for a drive-in restaurant, the circuits of Figs. 2a and 2b being interconnected to complete the system by four connections indicated by the small letters a, b, c and d, all relays being shown in their unoperated de-energized condition.

For purposes of discussion the system will be described as one which is capable of handling one hundred substations at one time. The one hundred sub-stations may correspond to one hundred automobile parking bays in the parking lot of a drive-in restaurant, there being ten rows of sub-stations with ten sub-stations in each row. In accordance with applicants matrix identification arrangement, each row will be assigned a different capital letter with the letter I being omitted to avoid possible confusion, letters A, B, C, D, E, F, G, H, J and K corresponding to rows 1 through 10, respectively. The ten sub-stations in each row are num- .bered consecutively 1 through 10. The numbers correspond to units in a decimal system, and the letters correspond to tens in a decimal system. Accordingly, if the sub-stations had instead been simply labeled numerically from 1, 2, 3, 4 97, 98, 99 and 100, it will be understood that for example station No. A-l in our matrix arrangement would be station No. 1, our station No. B-3 would be station No. 23, our station No. D-8 would be station No. 48, etc.

A visual display of the one hundred sub-stations may be seen on the call (i.e. order) display panel 12 of the central station control console 10 in Fig. 1. The central station may be the kitchen of the drive-in restaurant. The front of panel 12 comprises a flat sheet of transparent glass or plastic material such as Lucite or Plexiglas. On the rear surface of the sheet is a thin layer of black paint or printers ink which is apertured with a left-hand vertical row of letters A, B, C, D, E, F, G, H and K and with ten parallel horizontal rows of numbers 1 through. 10. The letters and numbers are backed up by conventional means such as a thin layer of white translucent paint which may be sprayed on to cover the entire rear surface area of the sheet and which may fill part or all of each letter and number aperture. Positioned behind the panel is an array of small electric lamps 14, some of which are shown in Fig. 2a. Aligned directly behind each apertured letter and each apertured number is the filament of a different one of the lamps. When there are no customers present at any of the sub-stations and when there may be customers present but they have all placed their orders, panel 12 will appear to the central station operator as a dark area with no'letters or numerals visible.

When customers at one or more sub-stations have signalled (i.e. called) the central station and are awaiting an answer from the central station so as to be placed in two-way voice communication with the central station, a lamp will be illuminated behind the number in the row corresponding to the sub-station which has signalled. As an additional refinement, the left-hand vertical row of letters have been provided and the lamp behind the letter for the corresponding row will also be illuminated. As illustrated in Fig. 1 for example, the following sub-stations have called and are awaiting an answer from the central station: A-l, A-Z, A-3, A-4, A-S, A-6, A-7, A8, A-9, A-lO, B-1, B-Z, B4, B-4, B-S, B-6, C-l, C2, C3, D-l, E2, F-4, G-S, H-9, L2 and K4. Below panel 12 on console 10-is a horizontal row of ten selector switch pushbuttons 16 lettered A through K (1 being omitted). Vertically aligned below the letter pushbuttons are ten number selector switch pushbuttons 18 numbered 1 through 10. When the central station operator is ready to answer any particular one of the sub-stations which have signalled and are waiting, he simply depresses the single letter button and the single number button which correspond to the particular sub-station. For example, in order to answer sub-station A-l, the operator depresses the letter button A and the number button 1. By means of circuitry which will be explained hereinafter, this serves to extinguish lamp 1 in row A, but the lamp A will remain illuminated since the other nine sub-stations in row A have signalled and are still waiting to be answered. Those letters and numbers which happen to be illuminated ap pear white against a dark background. Alternatively, instead of providing the letters and numbers on panel 12, each lamp may bear its own respective letter or number, for example by suitable painting on the bulb.

- By means of our unique matrix arrangement for identifying and selecting particular sub-stations which have called and await an answer, it is possible to provide a master control cabinet 10 at the central station which does not have to contain relays in the same cabinet and which permits a call display panel capable of indieating all sub-stations simultaneously but yet occupying only a small surface area in comparison with display panels of other types of electronic ordering systems. Moreover, it will be seen that our matrix selection arrangement requires only a relatively small total number of selector elements or switches in order to answer any one of a large number of sub-stations. In one construction, the active surface area of panel 12 is only approximately 8 x 9 inches, and the overall dimensions of the console 10 are only about as large as those of a conventional cash register. In order to prevent more than one letter pushbutton 16 and more than one number pushbutton 18 from being depressed at any one time, the letter and number pushbuttons are all mechanically interlocked by a conventional interlock mechanism.

Turning to Figs. 2a and 2b, complete connections and relays are shown for providing signalling and intercommunication between a representative sub-station (A-1) and the central station 10. In order to avoid unnecessarily burdensome duplication in the drawings, the completed connections, relays, switches and most of the lamps for the other ninetv nine sub-stations have been omitted. the necessary additional connections being represented by arrows and asterisks which will be explained as the description proceeds. Sub-station A-l may include a handset which is held by the patron and which includes a combination microphone-loudspeaker unit 20 (Fig. 2a) such as used in conventional inter-com systems. When not in use for voice communication with the central station, the patron may hang the handset on the car door or on a hook provided on a stationary post at the substation. Such post may su port an internally illuminated perspective-type menu holder such as disclosed in pending design application Ser. No. 45,688 filed April 11, 1957 by R. T. MacFarlane et al. and assigned to the same assignee as the present ap lication.

Before and after each sub-station has signalled and has been answered by the central station, each sub-station is provided with a program such as an entertainment program of music. The program circuit may be traced as follows. The sneaker coil of unit 20 is connected via line 21 to the fourth movable contact, and its normally mating fixed up er contact, of a normally deenergized order He call) relav A-l which has one terminal of its coil 22 grounded. The music line continues over connections 24 and 112 to the second movable contact, and its normally mating fixed upper contact, of a normally de-energized answer" relay A1 which has a coil 124. The music line continues over line 26 to the center tap terminal 28 of a coil 30 which is connected in the output of a high-fidelity amplifier 32. The input to the am lifier is connected via the normally closed left-hand pairs of contacts of a normally de-energized All-Stations relay 34 and over lines 35 and 36 to the output of a program source such as a music source 38 which may be a conventional record player or radio. As indicated by the branch line 39 and asterisk 40 above the answer relay A-1, similar parallel connections are made from the program line 26 to the second movable contact and its normally mating upper contact of each of the other ninety nine answer relays which in turn each have connections similar to connections 112 and 24 to the fourth movable contact and its normally mating fixed upper contact of a respective different one of the ninety nine other order relays. Such mating contacts of each of such other order relays being connected over a line similar to line 21 to the loudspeaker of a respective different one of the other ninety nine sub-stations.

When the patron at sub-station A-l desires to signal the central station 10 so as to be placed in two-way voice communication with the central station, the patron picks up his handset and throws call switch 42 momentarily to its spring-biased upper position which is the order position. The movable contact 43 of switch 42 is connected by line 41 to a suitable source of supply voltage, which may be 20 volts D.C. In Figs. 2a and 8 2b each of the power supply connections labeled +20" may be connected to a separate 20 volt D.C. power supply or instead to the +20 volt output terminal of a common power supply such as power supply 45 (Fig. 2b), the other output terminal being grounded for convenience.

The momentary closure of the call switch 42 causes a signalling path to be completed from sub-station A-l to central station 10 as follows. The +20 volt source is connected via line 41 and the movable contact 43 with its mating upper fixed contact and over line 44 to the upper terminal of the coil 22 of the A-l order relay. The resulting energization of the A-l order relay causes its first pair of contacts to close, which completes a holding circuit for coil 22 which may be traced from ground through coil 22, through its first pair of contacts now closed and over line 47 and through the normally closed first pair contacts of the A-l answer relay and over line 48 to the +20 volt source and hence back to ground. The holding circuit thus holds the A-l order relay energized even though the patron at sub-station A-l only momentarily closes switch 42 to its spring-biased order position and then releases it, which is normal procedure.

The second and third movable contacts of relay 22 are interconnected by a connection 50 so that, upon energization of relay 22, a circuit is completed as follows to illuminate the A lamp 14 behind the call or order signal panel 12 at central station 10. The circuit extends from the +20 volt source via line 49 and the nowclosed second and third pairs of contacts of relay 22 and their interconnection 50, over connection 52 and line 54 to the lower terminal of the A lamp 14, the other terminal of the lamp being grounded. The l lamp 14 is simultaneously illuminated by a line 58 which is completed to the +20 volt source over the same circuit including line 47 which serves as the holding circuit for relay 22. For simplicity, only the first four lamps of the first three rows (A, B, C) are illustrated in Fig. 2a. The upper terminal of each lamp is connected to ground. As indicated by the branch line 55 and asterisk 56, the lower terminal of A lamp 14 is also connected to the second movable contact of each of the other nine order relays (A-2, A-3, A-4, etc.) corresponding to row A so as to be energizable by any of the other nine row A sub-stations. Similarly, the lower terminal of each of the other letter lamps is connected over a line similar to line 54 to the second movable contact of each of the ten order relays which correspond to the particular letter row, so that the particular letter lamp may be energized by closing the call switch at any one of the ten sub-stations in the particular letter row. As indicated by the arrows, the lower terminal of each of the other nine number lamps (2, 3, "4," etc.) in row A is connected via a line similar to line 58 to the upper terminal of a corresponding one of the other nine order relay coils for row A so as to be energized from the holding circuit of such corresponding order relay. In a similar manner the lower terminal of each of the ten number lamps for each of the nine other letter rows is connected for energization via a line similar to line 58 to the upper terminal of a corresponding one of the ten order relays for the particular letter row.

The central station operator may observe on panel 12 that two or more sub-stations have signalled and are still waiting for an answer from the central station. Before answering each of such sub-stations individually to take the individual orders, the central station operator, in accordance with a novel feature of the invention, may desire to talk simultaneously to all of such sub-stations which are awaiting an, answer and yet not disturb the music to those other sub-stations which have been answered and for which the corresponding letter button '16 and number button 18 have been released mechanically by button R. For example, the operator may wish to announce special features on the menu. For this purpose, the operator "flips a switch 60 (Fig. 1 and Fig.

2b) to its spring-biased Standby position, thereby completing a circuit for a Standby relay 66 and for a Talk relay 68 as follows. An energization circuit for relay 66 extends from the 20 volt source through the movable contact 62 and its mating lower fixed contact of switch 60 and over line 64 to the coil of relay 66 back to ground. The resulting energization of relay 66 completes a circuit from ground through its coil and its nowclosed first pair of contacts over line 67 and through the coil of the Talk relay 68 back to ground, thereby energizing relay 68.

As a result of the energization of relays 66 and 68, a common talk channel (Standby channel) is established as follows to each of the sub-stations waiting for an answer. The central station operator speaks into the microphone-loudspeaker unit 59, functioning as a microphone, and over line 69 through the now-closed second pair of contacts of relay 68 to primary winding '72 of a transformer having connected across its secondary winding 73 a potentiometer 74. The slider of potentiometer 74 is a gain or volume adjustment and is connected by a lead 75 to the input of a voice amplifier 76. The output of amplifier 76 is connected across the primary winding 78 of an impedance matching transformer having a secondary winding 79 provided with two intermediate taps 80 and 93. As will be explained hereinafter, the following voice intelligence is transmitted over a line 94 from tap '93: the central station talk to all station (i.e. substations); also the central station single station talk on answer to an individual substation, and the order talk from such individual sub-station in reply.

Continuing again to trace the common talk channel, a connection is made from tap 8t} and line 81 through the now-closed second pair of contacts of relay 66 and along line 82 via the interconnection b between Figs. 2b and 2a and then over line 83 and to a line 84 by way of the de-energized A-1 answer relays normally closed upper pair of contacts constituted by its third movable contact with its fixed upper mating contact. From line '84 the circuit continues to line 21 and the A-1 substation loudspeaker 20 by way of the presently energized A-l order relays now closed upper pair of contacts constituted by its fourth movable contact with its fixed adjoining lower mating contact. As indicated by the branch line 85 and asterisk 86, the common talk channel is extended to similar contacts of each of the other ninety nine answer relays and ninety nine order relays. Accordingly, for each other de-energized answer relay and its corresponding presently energized order relay, a circuit is completed to a sub-station loudspeaker from line 85 over a line similar to line 83 and to a line similar to line 84 by way of each such other de-energized answer relays closed upper pair of contacts and then through the nowclosed upper pair of contacts of the presently energized corresponding order relay and finally over a line similar to line 21 to the microphone-loudspeaker of the corresponding sub-station. For those sub-stations which have not yet signalled and those which have signalled and have been answered by the central station operator having depressed and then later released the corresponding letter button 16 and number button 18, the musical program will continue uninterrupted and the common talk will not be heard, since each order relay corresponding to .CflCh of such sub-stations .will be de-energized and hence its fourth movable contact will not be in contact with itsfixed adjoining lower contact. In accordance with an optional auxiliary feature, the central station operator may have common talk not only with those sub-sta- 'tions which have signalled and have not been answered :blltfllSO simultaneously with the last sub-station, in point of time, which has signalled and haslbeen answered but for which the central station voperatorhas not yet mechanically released the corresponding letter button 16 andnumber button 18 by depressing the mechanical .re-

10 lease button R .on the central controlconsole '18. However, the path of communication between the central station and such last-mentioned sub-station will not follow the common talk channel, but rather will follow the single-station channel, as will be apparent from thefollowing description of the single-station channel.

Instead of having common talk with the sub-stations, the central station operator may wish to answer any particular one of the sub-stations which have signalled and to effect twoway communication with such particular sub-station. In the discussion which follows it will be assumed that the operator wishes to answer and have two-way communication with the No. Al sub-station, and accordingly in Figs. 2a and 2b there is shown the A1 sub-station, the A and l pushbuttons, the A order lamp with its 1 order lamp, the A tray lamp with its 1 tray lamp, the A isolation relay, the A-l order relay and the A-l answer relay.

In our unique matrix selection arrangement which permits anyone of a large number (e.g. of substations to be answered and placed in two-way communication by the provision of only a small total number (20) of manual selector elements (switches 16 and 18 in the illustrated embodiment), it is desirable to provide some means for preventing the possibility that the current flow in back circuits through one or more unselected answer relays may be sufficient to energize such answer relay even though its corresponding combination of letter button 16 and number button 18 has not been depressed by the operator. Such back circuits result from the multiple parallel connections of the answer relays, as will be apparent as the description proceeds. For example, in parallel with the A-l answer relay may be the series combination of the A-2 answer relay, the 13-2 answer relay and the B-1 answer relay. Similarly, in parallel with the B-1 answer relay may be the series combination of the B-2, C-2 and C-1 answer relays. In accordance with the invention means such as an open pair of contacts of an isolation relay are provided in series with each such series combination of answer relay coils so that while the pair of contacts remains open the unwanted back circuits are interrupted and only the desired answer relay coil may be energized when selected by the operator. Alternatively, the isolation relays and their pairs of contacts may be eliminated and each such pair of contacts re placed by a diode having its anode and cathode (or their equivalent elements) appropriately connected in series with the aforementioned series combination of answer relays so that direct current can flow in only one direction.

In Fig. 2a there is shown a relay 104 having six pairs of normally open contacts and a parallel connected second relay 103 having five pairs of normally open contacts. Four purposes of the invention, relays 103 and 104 (and others, if used) may be considered the equivalent of one relay (i.e. the A Isolation Relay) having eleven pairs of. normally open contacts. Using two or more parallel relays each with a small number of contact pairs often has certain practical advantages over the use of just one relay with a correspondingly larger number of contact pairs. Therefore, in the following description and claims the phrase isolation relay or isolation relay means is to be understood to include one or more relays performing the same basic functions as would one isolation relay with a larger number of contact pairs. A total of ten isolation relays are employed. The A isolation relay is for the A bank of ten answer relays (Ar-1, A-i2, etc.) and for the A bank of ten order relays (A.l, A-Z, etc), the B isolation relay is for the 5 bank of ten answer relays (B-l, B-Z, etc.) and for the B bank of ten order relays (B-l, B2 etc. and

SO OIL In order to answer sub-station A-l, the operator depresses the A pushbutton 'in the series of ten letter pushbuttons 16 and, either simultaneously or subseover line 69 and to line 70 quently, also depresses the 1 pushbutton in the series of ten number pushbuttons 18. Closure of the A pushbutton switch completes an energization circuit for the A isolation relay (103, 104) extending from the +20 volt supply terminal over line 102 and through the relay coil means (103, 104). The resultant closure of the first pair of contacts of the A isolation relay constituted by the first movable contact (labelled l) with its fixed adjoining lower contact, serves to complete part of an energization circuit for energizing the coil 106 of the A-l answer relay. Such circuit extends from the +26 volt source through the closed A button switch over line 102 and then from the upper junction of coils 103 and 106 through the aforementioned now-closed first pair of contacts and over line 105 and through the coil 106 of the A-l answer relay. In order to complete a circuit to ground so as to energize the Al answer relay, it is apparent that the 1 button switch must also be closed by the operator, as previously indicated. Upon energization of the A-l answer relay, its first movable contact breaks contact with its adjoining upper fixed contact, thereby interrupting the holding circuit for the coil of the Al order relay and hence causing the Al order relay to become de-energized. This in turn serves to extinguish or erase" the A order lamp and the 1 order lamp in row A of the lamps 14 behind the order or call signal panel 12.

As indicated by the arrow 130, the right-hand terminal of the l selector switch 18 is also connected to the lower terminal of nine other answer relay coils (i.e. B-l, C-l, D-l etc.). Similarly, as indicated by the arrow, the right-hand terminal of the "2 selector switch 18 is connected to the lower terminal of ten different answer relays (A-2, B-2, C-2 etc.) each of which is the second answer relay in a different one of the ten letter banks of answer relays. Similarly, 3 selector switch 18 is connected to the lower terminal of another ten different answer relays (A-3, B-3, C-3, etc.), and so on. Also, as ind cated by the arrow, the second movable contact of the A isolation relay is connected to the top terminal of the A-2 answer relay coil in the A bank of answer relays. Similarly, the third movable contact of the A isolation relay is connected to the top terminal of the A-3 answer relay in the A bank of answer relays, and so on.

By disabling the A-l order relay, energization of the A-l answer relay also serves to disconnect the microphone-loudspeaker line 21 of sub-station A-l from the common talk (Standby) channel and to connect the microphone-loudspeaker line 21 instead to the singlestation talk channel which may be traced as follows. When the central station operator flips the switch 60 to its spring-biased Talk position, this completes an energization circuit for the Talk relay coil 68 extending from the +20 volt source via the movable contact 62 and its fixed upper contact and over line 108 and through coil 68 to ground. The speech of the central station operator may now be transmitted from microphone 59 via the now-closed second pair of relay 68 contacts constituted by the second movable contact now making contact with its adjoining righthand fixed contact. By means discussed in connection with the functioning of the common talk" channel, the voice signal is then amplified by amplifier 76 and appears at the transformer secondary winding 79. The singlestation talk channel, then continues from tap 93 over line 94 and to a line 109 via the now-closed first pair of relay 68 contacts constituted by the first movable contact now making contact with its adjoining right-hand fixed contact. From line 109 the single-station talk channel then proceeds via the now-closed eleventh pair of contacts of the A isolation relay and over line 110 to a line 111. Line 111 is connected to a line 112 via the now-closed second pair of contacts of the now-energized A-l answer relay constituted by the second mov- 12 able Contact now making contact with its adjoining lower fixed contact. The single-station talk channel is then completed from line 12 via the again-closed fourth pair of contacts of the now-de-energized A-l order relay and over line 24 to the speaker 20 at the A-1 sub-station. Thus, the operator is now able to ask the A-1 sub-station patron which items from the menu he desires.

In order to permit the A-l sub-station patron to reply, the central station operator releases the switch 60 to its central neutral position, which de-energizes relay 68, The voice signal from the A-l sub-station patron to the central station 10 speaker 59 follows the same path as the central station operators voice signal between lines 21 at the A-l sub-station and line 109 extending from the eleventh pair of contacts of the A isolation relay. However, between line 109 and the central station speaker 59, the patrons voice signal follows a somewhat different path, which includes the interconnection 118 of relay 68 and the second movable contact of relay 68 which again makes contact with its adjoining left-hand fixed contact. From line 70 to the patrons voice signal is amplified by amplifier 76 and from tap 93 is transmitted over line 94 and to a connection 119 via the first movable contact of relay 68 which again makes contact with its adjoining left-hand fixed contact. Connection 119 leads to the slider 120 of a potentiometer 121 and finally to the speaker 59. Slider 120 may be adjusted so as to adjust the volume of the patrons voice as heard on speaker 59.

As indicated by the branch line 113 and asterisk 114, connections similar to line 111 are made from line to the fixed lower contact adjoining the second movable contact of the each of the other nine answer relays (A-2, A-3, etc.) in the A" bank of answer relays. Also, as indicated by the branch line and asterisk 116, similar connections are made from line 109 to the eleventh movable contact of each of the other nine letter isolation relays (B, C, etc.) and the corresponding adjoining lower fixed contact of each such isolation relays is connected to the corresponding answer relay in a manner similar to connections 110 and 111 etc. In passing, it is to be noted that line 109 is preferably, but not necessarily, connected to a normally open contact (No. 11) of the isolation relay rather than directly to line 111. This is done so as to minimize cross-talk which otherwise might occur. However, if the isolation relays were omitted as previously suggested, then line 109 could be connected directly to line 111.

In accordance with a feature of the invention, means are provided so that the central station can talk to a particular sub-station when switch 60 is on Talk even though the patron mistakenly continues to hold switch 42 closed against the spring-bias in its order position, thereby maintaining the order relay energized. This is accomplished by means of a by-pass circuit including a connection 122 from line 112 which connects with line 84 via the presently closed third movable contact and its adjoining lower fixed contact of the answer relay, the circuit being completed to the microphone-speaker 20 via the order relays movable fourth contact which is now in contact with its adjoining lower fixed contact. When the central station operator has completed his conversation with the A-l sub-station, he depresses the master release button R which restores the A" button 16 and 1 button 18 to their original open condition as they were before they were depressed.

If the central station wishes to talk simultaneously to all of the sub-stations, then the operator flips the switch 89 from its neutral center position to its All Stations position which completes an energization circuit for the All Stations" relay 34 from the +20 volt power supply 45 and connection 87 to a line 88 via the movable switch contact 137 and its adjoining lower right-hand fixed contact. Line 88 is connected in turn to relay 34. Closure of switch 89 in its All Stations position also completes 13 an energization circuit for the Talk relay 68 from source 45 and connection 87 to line 92 via the movable switch contact 137 and its adjoining lower left-hand fixed contact. From line 92 the circuit continues over line 64 to energize relay 66. Energizauon of relay 66 causes the Talk relay 68 to also be energized, as previously explained. The All-Stations channel may be traced as.

follows. Between microphone '59 and the transformer secondary winding 79 the All-Stations path is the same as the common talk path and the Single-Station path previously explained. From tap '93 the All-Station channel continues over line '94 and to line '96 via the Talk relays first movable contact which now makes contact with its adjoining right-hand contact fixed contact. Line 96 is connected to a voltage-divider network comprising resistors 96-101 to serve as an adjustable attenuation network for the All-Station voice signal. The pick-ofi line is connected to either the decibel point or the 6 decibel point 102 or the" 12 decibel point, depending upon the total number'of stations employed in the system. From line 91 the channel continues to the first movable contact of relay '34 which is now in contact with its adjoining right-hand fixed contact. The All- Stations voice signal is then amplified by amplifier 32 and continues to the speakers of the various sub-stations in the manner explained for the program or music channel.

Additionally, as respects those substations which have signalled the central station but have not yet been answered thereby, a talk circuit is established from the tap 86 of the transformer'79 through the conductor '81, upper contact of the relay 66, conductor 82, conductor '83 (Fig. 2a) upper contact 3 of the relay 1'06, conductor 84, and the lower fixed contact 4 of the energized order relay'22 and through the conductor 21 to the speaker 20.

If it is desired to maintain a daily record of the total number of calls that have been answered for all substations, an integrator. or counting arrangement maybe provided. Each of the one hundred answer relays has its fixed adjoining contact beneath its first movable contact connected via a line 124 to a conventional counter '125. The similar parallel connections to the movable first contact and its adjoining lower fixed contact are indicated by the branch line 126 and asterisk 127. Counter 125 may be a conventional electrical pulse counter wherein the counter wheel means are indexed ahead each time an answer relay is energized so as to send a 20 volt impulse to the counter coil.

If it is desired to have a numerical indication at the central station of the total number of calls on panel 12 which are still waiting to be answered, then counter 125 can be replaced by a conventional add-subtract impulse counter having one terminal of its subtract coil connected to line 124 and having the other terminal .of its subtract coil grounded. Such 'counters add coil would have one terminal grounded and the other terminal connected to the lower contact of a fifth pair of normally open contacts provided in each of the order relays, the other contact of such fifth pair being-connected to a 20 volt source. Thus, each time an order relay is energized it serves to impulse the add coil to index the counter wheel means ahead, while each time an answer relay is energized it serves to impulse the subtract coil to index the counter wheel means backwards.

In order to signal the central station that a patron is finished eating and that the empty service tray can be picked up by the waitress, a Tray signal panel is provided at the central station. Such panel may be similar in design to the order signal panel 12. It may include ten horizontal'rows of lamps, each row having eleven lamps which are normally extinguished. The first lamp 140 in each row being arranged to show a different letter (A through K, omitting I) and the other ten lamps in each row being numbered 1 through 10.

"14 Alternatively, and as shown in Fig. 2a, each of the letter lamps may be arranged to be illuminated continuously by connecting such lamps permanently across the power supply. Each of the number lamps 139 is connected to the lower fixed contact of the respective sub-station signalling switch 43.

It is to be understood that the drawing and specification are given merely by way of example and illustration of one embodiment of the present invention. Various modifications will now become apparent to those skilled in theart without departing from the spirit and scope or the invention as defined by the appended claims.

We claim:

1. A communication system comprising a series of substations each having microphone and loudspeaker means, a central station having microphone and loudspeaker means, indicator means at said central station operative upon energization to identify visibly a particular sub-station which has signalled said central station and whichis waiting to be placed in voice communication therewith, a series of call relays wherein there is a diiferent call relay corresponding to each different one of said sub-stations, a series of answer relays wherein there is a different answer relay corresponding to each difierent one of said substations, each call relay having a plurality of normally open contacts, each answer relay having a pair of .normally closed contacts and a pair of normally open contacts, a normally open control circuit for each of said sub-stations which includes a normally open call switch and which is connected to energize the corresponding one of said call relays upon closure of said call switch, normally open signalling circuit means including said open contacts of each of said call relays and electrically coupled to said central station indicator means to energize said indicator means upon closure of any one of said call switches to energize the respective call relay and close its open contacts, and normally open control circuit means for each of said answer relays including normally open answer switch means at said central station for energizing upon closure of said answer switch means the particular one of'said answer relays which corresponds to a particular sub-station having signalled said central station, each answer relay and its correspond-call relay having a diiferent disablingcircuit including said pairof normally closed answer relay contacts adapted to de-energize said call relay and again open its normally open contacts :to de-energize said indicator means upon energization of .said answer relay and its correspounding sub-station microphone-speaker means having a diiferent normally open single-station voice communication connection including said pair of normally open answer relay contacts adapted to complete a single-station voice communication path between said last-mentioned pair of contacts and said corresponding sub-station microphone-speaker means upon closure of said last-mentioned pair of contacts.

.2..A communication system according to claim 1 wherein each of said call relays has a pair "of normally closed contacts-and each of said answerrelays has a 'second pair of normally closed contacts and wherein there is provided an entertainment program channel including an entertainment program source for transmitting said program normally to said loudspeaker means of each of said sub-stations, there being provided a different normally closed program connection between said program channel and said loudspeaker means of each of said substations, said program connection for each sub-station including said pair of normally closed contacts of the corresponding call relay and said second pair of normally closed contacts of the corresponding answer relay so that the opening of said pair of normally closed contacts of said corresponding call relay upon energization thereof serves to open the respective program connection to disconnect the loudspeaker means of the corresponding substation from said program channel and the subsequent opening of said second pair of normally closed contacts of said corresponding answer relay upon energization thereof serves to maintain in an open condition said respective program connection.

3. A communication system according to claim 1 wherein each of said call relays has a pair of normally closed contacts forming part of the corresponding normally open single-station voice communication connection including said pair of normally open answer relay contacts, and wherein each of said answer relays has an additional pair of normally open contacts one contact of which is connected with one contact of said first-mentioned pair of normally openanswer relay contacts, and wherein each of said call relays has an additional pair of normally open contacts connected in circuit with the other contact of said additional pair of normally open answer relay contacts so that said pair of normally closed call relay contacts is by-passed and a single-station voice communication connection is thus nevertheless established between the corresponding sub-station microphone-speaker means and said first-mentioned pair of normally open answer relay contacts notwithstanding the fact that the person at the corresponding sub-station mistakenly continues to maintain closed his call switch, thereby maintaining the corresponding call relay energized and thus maintaining open its pair of normally closed contacts, even though said central station has already energized the corresponding answer relay which otherwise would have de-energized said corresponding call relay.

4. A communicating and signalling system comprising, a. central station including an entertainment signal source, a plurality of substations each of which includes a transducer, each of said substations having relay means associated therewith which in a first condition of operation connects the transducer of an individual substation to said entertainment signal source and in a second condition of operation disconnects the transducer from said source and operates an indicator at said central station, and relay means selectively operated from said central station for establishing a communication circuit between said central station and a selected one of said substations in either condition of operation of said first mentioned relay means.

5. A communication and signalling system comprising, a central station including an entertainment signal source, a plurality of substations each of which includes a transducer, each of said substations having a first relay means associated therewith which in a first condition of operation connects the transducer of an individual substation to said entertainment signal source and in a second condition of operation disconnects the transducer from said source and operates an indicator at said central station, second relay means selectively operated from said central station for establishing an individual con1- munication circuit between said central station and a selected one of said substations in either condition of operation of said first relay means, and third relay means operated from said central station for establishing a common communication circuit between said central station and all of those substations whose first relay means are in their second condition of operation.

6. A communication and signalling system as set forth in claim 5 including fourth relay means operated from said central station for establishing a common communication circuit between said central station and all of those substations whose first relay means are in their first condition of operation.

7. A communication and signalling system comprising, a central station including an entertainment source and a communication source, a plurality of substations each of which includes a transducer, relay means associated with each of said substations for connecting the transducer thereof to said entertainment source in a first condition of operation and for disconnecting said entertainment source from a respective transducer and establishing a signal circuit between the central station and the substation with which said relay is associated in its second condition of operation, a first talking circuit connected to all of those particular substations whose relay means is in its first condition of operation, a second talking circuit connected to all of those particular substations whose relay means is in its second condition of operation, and a single switch for simultaneously connecting the communication source of said central station to said first and second talking circuits.

8. A communication and signalling system as set forth in claim 7 including means for establishing a third talking circuit between the communication source of said central station and a selected one of said substations.

9. A communication and signalling system comprising, a central station including an entertainment source and a communication source, a plurality of substations each of which includes a transducer, relay me:.ns associated with each of said substations for connecting the transducer thereof to said entertainment source in a first condition of operation and in a second condition of operation disconnecting the transducer from said entertainment source and operating an indicator at said central station, a plurality of selecting switches the selective actuation of which establishes a talking circuit connected to individual selected ones of said substations, a single switch means operable in one condition of actuation to connect said communicating source to a selected one of said substations through actuation of selected ones of selecting switches and operable in a second condition of actuation to connect said communication source to all of those substations whose relays are in their second condition of operation regardless of the condition of actuation of said selecting switches.

References Cited in the file of this patent UNITED STATES PATENTS 2,549,676 Dunn et al. Apr. 17, 1951 2,559,898 Plawczyk July 10, 1951 2,688,657 Wilson Sept. 7, 1954 FOREIGN PATENTS 744,872 Great Britain Feb. 15, 1956 

